The domination number and the least QQ-eigenvalue

A vertex set $D$ of a graph $G$ is said to be a dominating set if every vertex of $V(G)\setminus D$ is adjacent to at least a vertex in $D$, and the domination number $\gamma(G)$ ($\gamma$, for short) is the minimum cardinality of all dominating sets of $G$. For a graph, the least $Q$-eigenvalue is the least eigenvalue of its signless Laplacian matrix. In this paper, for a nonbipartite graph with both order $n$ and domination number $\gamma$, we show that $n\geq 3\gamma-1$, and show that it contains a unicyclic spanning subgraph with the same domination number $\gamma$. By investigating the relation between the domination number and the least $Q$-eigenvalue of a graph, we minimize the least $Q$-eigenvalue among all the nonbipartite graphs with given domination number.Comment: 13 pages, 3 figure

Signless Laplacian spectral radii of graphs with given chromatic number

AbstractLet G be a simple graph with vertices v1,v2,…,vn, of degrees Δ=d1⩾d2⩾⋯⩾dn=δ, respectively. Let A be the (0,1)-adjacency matrix of G and D be the diagonal matrix diag(d1,d2,…,dn). Q(G)=D+A is called the signless Laplacian of G. The largest eigenvalue of Q(G) is called the signless Laplacian spectral radius or Q-spectral radius of G. Denote by χ(G) the chromatic number for a graph G. In this paper, for graphs with order n, the extremal graphs with both the given chromatic number and the maximal Q-spectral radius are characterized, the extremal graphs with both the given chromatic number χ≠4,5,6,7 and the minimal Q-spectral radius are characterized as well

Research on the influence mechanism and optimisation of urban greenway network use pattern based on multi-source data - a case study of Guangzhou, China

Urban greenways have become the major venue for inhabitants to relax and exercise in recent years. The impact of non-motorised travel and urban recreation on greenways grows. So the primary purpose of improving and enhancing greenway design is to meet users\u27 recreational and leisure demands. However, general greenway planning usually contrasts with actual resident use. More study is necessary to assess whether the efficiency of urban greenway use is compatible with planning goals. Using multiple source data to analyse urban dwellers\u27 use patterns and the factors that impact them might provide a new perspective on designing and optimising greenways. Using Guangzhou as an example, this paper investigates the use pattern of greenways and their spatial and temporal distribution characteristics based on the user movement trajectory data/ distribution map, identifies potential high-use sections of greenways, and then selects the factors affecting the use intensity of greenways, and performs spatial correlation analysis using the geographical detector. Finally, the weighting of different influencing factors provides a reasonable basis for the optimal construction and improvement of urban greenways

MicroRNA-595 promotes osteogenic differentiation of bone marrow mesenchymal stem cells by targeting HMGA2

Purpose: To investigate the effect of miR-595 on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs).Methods: Human BMSCs were osteogenically differentiated, and protein expression of alkaline phosphatase (ALP), osteocalcin (OCN), and Runt-related transcription factor 2 (RUNX2) were evaluated by western blot. Expression of miR-595 was measured by quantitative reverse transcription (qRT-PCR). The effect of miR-595 on viability of BMSCs was determined by MTT assay. Osteogenic differentiation of BMSCs was assessed by ALP and Alizarin red S (ARS) staining. The target gene of miR-595 was predicted by TargetScan analysis and validated by luciferase activity assay.Results: MiR-595 expression was higher in osteogenically differentiated BMSCs than in undifferentiated BMSCs (p < 0.01). Osteogenic ALP, OCN, and RUNX2 were also upregulated (p < 0.01). MiR-595 expression increased the viability of BMSCs, mineralized bone matrix formation, and ALP activity. High mobility group AT-hook 2 (HMGA2) expression was lower in osteogenically differentiated BMSCs and was found to be a target of miR-595. Overexpression of HMGA2 attenuated the miR-595-induced increase in cell viability, ALP activity, mineralized bone matrix formation, and osteogenic gene expression in BMSCs.Conclusion: The miR-595/HMGA2 axis is involved in osteogenic differentiation of BMSCs suggesting that it is a promising therapeutic target for osteoporosis

Genomic epidemiology of Vibrio cholerae reveals the regional and global spread of two epidemic non-toxigenic lineages

Non-toxigenic Vibrio cholerae isolates have been found associated with diarrheal disease globally, however, the global picture of non-toxigenic infections is largely unknown. Among non-toxigenic V. cholerae, ctxAB negative, tcpA positive (CNTP) isolates have the highest risk of disease. From 2001 to 2012, 71 infectious diarrhea cases were reported in Hangzhou, China, caused by CNTP serogroup O1 isolates. We sequenced 119 V. cholerae genomes isolated from patients, carriers and the environment in Hangzhou between 2001 and 2012, and compared them with 850 publicly available global isolates. We found that CNTP isolates from Hangzhou belonged to two distinctive lineages, named L3b and L9. Both lineages caused disease over a long time period with usually mild or moderate clinical symptoms. Within Hangzhou, the spread route of the L3b lineage was apparently from rural to urban areas, with aquatic food products being the most likely medium. Both lineages had been previously reported as causing local endemic disease in Latin America, but here we show that global spread of them has occurred, with the most likely origin of L3b lineage being in Central Asia. The L3b lineage has spread to China on at least three occasions. Other spread events, including from China to Thailand and to Latin America were also observed. We fill the missing links in the global spread of the two non-toxigenic serogroup O1 V. cholerae lineages that can cause human infection. The results are important for the design of future disease control strategies: surveillance of V. cholerae should not be limited to ctxAB positive strains

Paeonol Attenuated Inflammatory Response of Endothelial Cells via Stimulating Monocytes-Derived Exosomal MicroRNA-223

Introduction: Paeonol, an active compound isolated from the radix of Cortex Moutan, has been shown to have anti-atherosclerosis effects by regulating blood cells’ function and protecting vascular cells injury. Besides, emerging evidences has proven that exosomes might play a pivotal role in intercellular communication by transmiting proteins and microRNAs from cell to cell. However, the relationship between monocytes-derived exosomal microRNA-223 and vascular inflammation injury along with paeonol’ effects are still not clear.Objective: Our study aimed to explain whether paeonol’s protective effect on inflammatory response is related to the regulation of exosomal microRNA-223 in the VECs.Methods: ApoE−/− mice were fed with high fat diet to replicate the AS model. HE staining and immunohistochemistry was used to detect inflammatory response of aorta. The expression of IL-1β and IL-6 were detected by ELISA. Western blot was used to detect the expression of STAT3, pSTAT3, ICAM-1 and VCAM-1. qRT-PCR was used to detect miR-223 expression. Exosomes were extracted from THP-1 cells by differential centrifugation and observed by transmission electron microscope. Observation of exosomes uptake into HUVECs was realized by laser microscopy. miR-223 target gene was detected by double luciferase gene report test.Results:In vivo experiments confirmed that paeonol restricted atherosclerosis development and increased miR-223 expression, inhibited STAT3 pathway in ApoE−/− mice. In vitro, miR-223 showed robust presence in THP-1 cells and undetectable in HUVECs. And we had observed that miR-223 could be internalized from THP-1 cells into HUVECs taking exosomes as a carrier. Paeonol obviously increased miR-223 expression in co-cultured HUVECs and exosomes in concentration dependent manner, compared to LPS group. In addition, paeonol relieved inflammatory secretion, adhesion and STAT3 expression in HUVECs, which could be inverted after miR-223 inhibitor transfection into THP-1 cells.Conclusion: Paeonol could increase the expression of miR-223 in THP-1 derived exosomes and in HUVECs after uptake of exosomes, whereas decrease the expression of STAT3, p-STAT3 in HUVECs. Ultimately paeonol decreased the expression of IL-1β, IL-6, ICAM-1, VCAM-1 in HUVECs and alleviated adhesion of THP-1 cells to HUVECs